OpenRaiser/Intern-Atlas huggingface dataset:
Evolving Delta-oriented Software Product Line Architectures
Venue: arXiv cs.SE 2014
Year: 2014

Diversity is prevalent in modern software systems. Several system variants exist at the same time in order to adapt to changing user requirements. Additionally, software systems evolve over time in order to adjust to unanticipated changes in their application environment. In modern software development, software architecture modeling is an important means to deal with system complexity by architectural decomposition. This leads to the need of architectural description languages that can represent spatial and temporal variability. In this paper, we present delta modeling of software architectures as a uniform modeling formalism for architectural variability in space and in time. In order to avoid degeneration of the product line model under system evolution, we present refactoring techniques to maintain and improve the quality of the variability model. Using a running example from the automotive domain, we evaluate our approach by carrying out a case study that compares delta modeling with annotative variability modeling.
CD2Alloy: Class Diagrams Analysis Using Alloy Revisited
Venue: arXiv cs.SE 2014
Year: 2014

We present CD2Alloy, a novel, powerful translation of UML class diagrams (CDs) to Alloy. Unlike existing translations, which are based on a shallow embedding strategy, and are thus limited to checking consistency and generating conforming object models of a single CD, and support a limited set of CD language features, CD2Alloy uses a deeper embedding strategy. Rather than mapping each CD construct to a semantically equivalent Alloy construct, CD2Alloy defines (some) CD constructs as new concepts within Alloy. This enables solving several analysis problems that involve more than one CD and could not be solved by earlier works, and supporting an extended list of CD language features. The ideas are implemented in a prototype Eclipse plug-in. The work advances the state-of-the-art in CD analysis, and can also be viewed as an interesting case study for the different possible translations of one modeling language to another, their strengths and weaknesses.
CDDiff: Semantic Differencing for Class Diagrams
Venue: arXiv cs.SE 2014
Year: 2014

Class diagrams (CDs), which specify classes and the relationships between them, are widely used for modeling the structure of object-oriented systems. As models, programs, and systems evolve over time, during the development lifecycle and beyond it, effective change management is a major challenge in software development, which has attracted much research efforts in recent years. In this paper we present cddiff, a semantic diff operator for CDs. Unlike most existing approaches to model comparison, which compare the concrete or the abstract syntax of two given diagrams and output a list of syntactical changes or edit operations, cddiff considers the semantics of the diagrams at hand and outputs a set of diff witnesses, each of which is an object model that is possible in the first CD and is not possible in the second. We motivate the use of cddiff, formally define it, and show how it is computed. The computation is based on a reduction to Alloy. The work is implemented in a prototype Eclipse plug-in. Examples show the unique contribution of our approach to the state-of-the-art in version comparison and evolution analysis.
Generative Software Development
Venue: arXiv cs.SE 2014
Year: 2014

Generation of software from modeling languages such as UML and domain specific languages (DSLs) has become an important paradigm in software engineering. In this contribution, we present some positions on software development in a model based, generative manner based on home grown DSLs as well as the UML. This includes development of DSLs as well as development of models in these languages in order to generate executable code, test cases or models in different languages. Development of formal DSLs contains concepts of meta-models or grammars (syntax), context conditions (static analysis and quality assurance) as well as possibilities to define the semantics of a language. The growing number and complexity of DSLs is addressed by concepts for the modular and compositional development of languages and their tools. Moreover, we introduce approaches to code generation and model transformation. Finally, we give an overview of the relevance of DSLs for various steps of software development processes.
Exploiting Social Network Structure for Person-to-Person Sentiment Analysis
Venue: arXiv cs.SI 2014
Year: 2014

Person-to-person evaluations are prevalent in all kinds of discourse and important for establishing reputations, building social bonds, and shaping public opinion. Such evaluations can be analyzed separately using signed social networks and textual sentiment analysis, but this misses the rich interactions between language and social context. To capture such interactions, we develop a model that predicts individual A's opinion of individual B by synthesizing information from the signed social network in which A and B are embedded with sentiment analysis of the evaluative texts relating A to B. We prove that this problem is NP-hard but can be relaxed to an efficiently solvable hinge-loss Markov random field, and we show that this implementation outperforms text-only and network-only versions in two very different datasets involving community-level decision-making: the Wikipedia Requests for Adminship corpus and the Convote U.S. Congressional speech corpus.
Distributed Resource Allocation in 5G Cellular Networks
Venue: arXiv cs.NI 2014
Year: 2014

The 5G cellular wireless systems will have a multi-tier architecture consisting of macrocells, different types of licensed small cells and D2D networks to serve users with different quality-of-service (QoS) requirements in a spectrum efficient manner. Distributed resource allocation and interference management is one of the fundamental research challenges for such multi-tier heterogeneous networks. In this chapter, we consider the radio resource allocation problem in a multi-tier orthogonal frequency division multiple access (OFDMA)-based cellular (e.g., 5G LTE-A) network. In particular, we present three novel approaches for distributed resource allocation in such networks utilizing the concepts of stable matching, factor-graph based message passing, and distributed auction. We illustrate each of the modeling schemes with respect to a practical radio resource allocation problem. In particular, we consider a multi-tier network consisting a macro base station (MBS), a set of small cell base stations (SBSs) and corresponding small cell user equipments (SUEs), as well as D2D user equipments (DUEs). There is a common set of radio resources (e.g., resource blocks [RBs]) available to the network tiers (e.g., MBS, SBSs and DUEs). The SUEs and DUEs use the available resources (e.g., RB and power level) in an underlay manner as long as the interference caused to the macro tier (e.g., macro user equipments [MUEs]) remains below a given threshold. Followed by a brief theoretical overview of the modeling tools (e.g., stable matching, message passing and auction algorithm), we present the distributed solution approaches for the resource allocation problem in the aforementioned network setup. We also provide a brief qualitative comparison in terms of various performance metrics such as complexity, convergence, algorithm overhead etc.
Full-Duplex Relay with Jamming Protocol for Improving Physical-Layer Security
Venue: arXiv cs.IT 2014
Year: 2014

This paper proposes a jointly cooperative relay and jamming protocol based on full-duplex (FD) capable relay to increase the source-destination secrecy rate in the presence of different types of eavesdroppers. In this so called \textit{FD-Relay with jamming (FDJ)} protocol, the FD-Relay, first, simultaneously receives data and sends jamming to the eavesdropper, and, then, forwards the data, while the source jams the eavesdropper. Achievable secrecy rates of the proposed FDJ in presence of different eavesdropper types and self-interference (SI) are derived and compared with those of the traditional half-duplex (HD) relay. The adaptive power allocation for secrecy rate maximization in a multi-carrier scenario for both proposed FDJ and HD-Relay is formulated as a non-convex optimization problem and corresponding iterative solution algorithm is developed using the difference-of-two-concave-functions (DC) programming technique. The simulation results confirm that FDJ offers significant improvements in the secrecy rate over the HD-Relay.
Towards Knowledge-Enriched Path Computation
Venue: arXiv cs.DB 2014
Year: 2014

Directions and paths, as commonly provided by navigation systems, are usually derived considering absolute metrics, e.g., finding the shortest path within an underlying road network. With the aid of crowdsourced geospatial data we aim at obtaining paths that do not only minimize distance but also lead through more popular areas using knowledge generated by users. We extract spatial relations such as "nearby" or "next to" from travel blogs, that define closeness between pairs of points of interest (PoIs) and quantify each of these relations using a probabilistic model. Subsequently, we create a relationship graph where each node corresponds to a PoI and each edge describes the spatial connection between the respective PoIs. Using Bayesian inference we obtain a probabilistic measure of spatial closeness according to the crowd. Applying this measure to the corresponding road network, we obtain an altered cost function which does not exclusively rely on distance, and enriches an actual road networks taking crowdsourced spatial relations into account. Finally, we propose two routing algorithms on the enriched road networks. To evaluate our approach, we use Flickr photo data as a ground truth for popularity. Our experimental results -- based on real world datasets -- show that the paths computed w.r.t.\ our alternative cost function yield competitive solutions in terms of path length while also providing more "popular" paths, making routing easier and more informative for the user.
Particle Swarm Optimized Fuzzy Controller for Indirect Vector Control of Multilevel Inverter Fed Induction Motor
Venue: arXiv cs.NE 2014
Year: 2014

The Particle Swarm Optimized (PSO) fuzzy controller has been proposed for indirect vector control of induction motor. In this proposed scheme a Neutral Point Clamped (NPC) multilevel inverter is used and hysteresis current control technique has been adopted for switching the IGBTs. A Mamdani type fuzzy controller is used in place of conventional PI controller. To ensure better performance of fuzzy controller all parameters such as membership functions, normalizing and de-normalizing parameters are optimized using PSO. The performance of proposed controller is investigated under various load and speed conditions. The simulation results show its stability and robustness for high performance derives applications.
F-formation Detection: Individuating Free-standing Conversational Groups in Images
Venue: arXiv cs.CV 2014
Year: 2014

Detection of groups of interacting people is a very interesting and useful task in many modern technologies, with application fields spanning from video-surveillance to social robotics. In this paper we first furnish a rigorous definition of group considering the background of the social sciences: this allows us to specify many kinds of group, so far neglected in the Computer Vision literature. On top of this taxonomy, we present a detailed state of the art on the group detection algorithms. Then, as a main contribution, we present a brand new method for the automatic detection of groups in still images, which is based on a graph-cuts framework for clustering individuals; in particular we are able to codify in a computational sense the sociological definition of F-formation, that is very useful to encode a group having only proxemic information: position and orientation of people. We call the proposed method Graph-Cuts for F-formation (GCFF). We show how GCFF definitely outperforms all the state of the art methods in terms of different accuracy measures (some of them are brand new), demonstrating also a strong robustness to noise and versatility in recognizing groups of various cardinality.
Narrow Proofs May Be Maximally Long
Venue: arXiv cs.CC 2014
Year: 2014

We prove that there are 3-CNF formulas over n variables that can be refuted in resolution in width w but require resolution proofs of size n^Omega(w). This shows that the simple counting argument that any formula refutable in width w must have a proof in size n^O(w) is essentially tight. Moreover, our lower bound generalizes to polynomial calculus resolution (PCR) and Sherali-Adams, implying that the corresponding size upper bounds in terms of degree and rank are tight as well. Our results do not extend all the way to Lasserre, however, where the formulas we study have proofs of constant rank and size polynomial in both n and w.
Graph Orientation and Flows Over Time
Venue: arXiv cs.DS 2014
Year: 2014

Flows over time are used to model many real-world logistic and routing problems. The networks underlying such problems -- streets, tracks, etc. -- are inherently undirected and directions are only imposed on them to reduce the danger of colliding vehicles and similar problems. Thus the question arises, what influence the orientation of the network has on the network flow over time problem that is being solved on the oriented network. In the literature, this is also referred to as the contraflow or lane reversal problem. We introduce and analyze the price of orientation: How much flow is lost in any orientation of the network if the time horizon remains fixed? We prove that there is always an orientation where we can still send $\frac{1}{3}$ of the flow and this bound is tight. For the special case of networks with a single source or sink, this fraction is $\frac12$ which is again tight. We present more results of similar flavor and also show non-approximability results for finding the best orientation for single and multicommodity maximum flows over time.
Design and Implementation of Intelligent Community System Based on Thin Client and Cloud Computing
Venue: arXiv cs.CY 2014
Year: 2014

With the continuous development of science and technology, the intelligent development of community system becomes a trend. Meanwhile, smart mobile devices and cloud computing technology are increasingly used in intelligent information systems; however, smart mobile devices such as smartphone and smart pad, also known as thin clients, limited by either their capacities (CPU, memory or battery) or their network resources, do not always meet users' satisfaction in using mobile services. Mobile cloud computing, in which resource-rich virtual machines of smart mobile device are provided to a customer as a service, can be terrific solution for expanding the limitation of real smart mobile device, but the resources utilization rate is low and the information cannot be shared easily. To address the problems above, this paper proposes an information system for intelligent community, which is composed of thin clients, wide band network and cloud computing servers. On one hand, the thin clients with the characteristics of energy efficiency, high robustness and high computing capacity can efficiently avoid the problems encountered in the PC architecture and mobile devices. On the other hand, the cloud computing servers in the proposed information system solve the problems of resource sharing barriers. Finally, the system is built in real environments to evaluate the performance. We deploy the proposed system in a community with more than 2000 residents, and it is demonstrated that the proposed system is robust and efficient.
Pruning, Pushdown Exception-Flow Analysis
Venue: arXiv cs.PL 2014
Year: 2014

Statically reasoning in the presence of exceptions and about the effects of exceptions is challenging: exception-flows are mutually determined by traditional control-flow and points-to analyses. We tackle the challenge of analyzing exception-flows from two angles. First, from the angle of pruning control-flows (both normal and exceptional), we derive a pushdown framework for an object-oriented language with full-featured exceptions. Unlike traditional analyses, it allows precise matching of throwers to catchers. Second, from the angle of pruning points-to information, we generalize abstract garbage collection to object-oriented programs and enhance it with liveness analysis. We then seamlessly weave the techniques into enhanced reachability computation, yielding highly precise exception-flow analysis, without becoming intractable, even for large applications. We evaluate our pruned, pushdown exception-flow analysis, comparing it with an established analysis on large scale standard Java benchmarks. The results show that our analysis significantly improves analysis precision over traditional analysis within a reasonable analysis time.
Two-Phase Bicriterion Search for Finding Fast and Efficient Electric Vehicle Routes
Venue: arXiv cs.DS 2014
Year: 2014

The problem of finding an electric vehicle route that optimizes both driving time and energy consumption can be modeled as a bicriterion path problem. Unfortunately, the problem of finding optimal bicriterion paths is NP-complete. This paper studies such problems restricted to two-phase paths, which correspond to a common way people drive electric vehicles, where a driver uses one driving style (say, minimizing driving time) at the beginning of a route and another driving style (say, minimizing energy consumption) at the end. We provide efficient polynomial-time algorithms for finding optimal two-phase paths in bicriterion networks, and we empirically verify the effectiveness of these algorithms for finding good electric vehicle driving routes in the road networks of various U.S. states. In addition, we show how to incorporate charging stations into these algorithms, in spite of the computational challenges introduced by the negative energy consumption of such network vertices.
DSP.Ear: Leveraging Co-Processor Support for Continuous Audio Sensing on Smartphones
Venue: arXiv cs.SD 2014
Year: 2014

The rapidly growing adoption of sensor-enabled smartphones has greatly fueled the proliferation of applications that use phone sensors to monitor user behavior. A central sensor among these is the microphone which enables, for instance, the detection of valence in speech, or the identification of speakers. Deploying multiple of these applications on a mobile device to continuously monitor the audio environment allows for the acquisition of a diverse range of sound-related contextual inferences. However, the cumulative processing burden critically impacts the phone battery. To address this problem, we propose DSP.Ear - an integrated sensing system that takes advantage of the latest low-power DSP co-processor technology in commodity mobile devices to enable the continuous and simultaneous operation of multiple established algorithms that perform complex audio inferences. The system extracts emotions from voice, estimates the number of people in a room, identifies the speakers, and detects commonly found ambient sounds, while critically incurring little overhead to the device battery. This is achieved through a series of pipeline optimizations that allow the computation to remain largely on the DSP. Through detailed evaluation of our prototype implementation we show that, by exploiting a smartphone's co-processor, DSP.Ear achieves a 3 to 7 times increase in the battery lifetime compared to a solution that uses only the phone's main processor. In addition, DSP.Ear is 2 to 3 times more power efficient than a naive DSP solution without optimizations. We further analyze a large-scale dataset from 1320 Android users to show that in about 80-90% of the daily usage instances DSP.Ear is able to sustain a full day of operation (even in the presence of other smartphone workloads) with a single battery charge.
Square Grid Points Coveraged by Connected Sources with Coverage Radius of One on a Two-Dimensional Grid
Venue: arXiv cs.CC 2014
Year: 2014

We take some parts of a theoretical mobility model in a two-dimension grid proposed by Greenlaw and Kantabutra to be our model. The model has eight necessary factors that we commonly use in a mobile wireless network: sources or wireless signal providers, the directions that a source can move, users or mobile devices, the given directions which define a user's movement, the given directions which define a source's movement, source's velocity, source's coverage, and obstacles. However, we include only the sources, source's coverage, and the obstacles in our model. We define Square Grid Points Coverage (SGPC) problem to minimize number of sources with coverage radius of one to cover a square grid point size of p with the restriction that all the sources must be communicable and proof that SGPC is in NP-complete class. We also give an Approx-Square-Grid-Coverage (ASGC) algorithm to compute the approximate solution of SGPC. ASGC uses the rule that any number can be obtained from the addition of 3, 4 and 5 and then combines 3-gadgets, 4-gadgets and 5-gadgets to specify the position of sources to cover a square grid point size of p. We find that the algorithm achieves an approximation ratio of . Moreover, we state about the extension usage of our algorithm and show some examples. We show that if we use ASGC on a square grid size of p and if sources can be moved, the area under the square grid can be covered in eight-time-steps movement. We also prove that if we extend our source coverage radius to 1.59, without any movement the area under the square gird will also be covered. Further studies are also discussed and a list of some tentative problems is given in the conclusion.
Green communication via Type-I ARQ: Finite block-length analysis
Venue: arXiv cs.IT 2014
Year: 2014

This paper studies the effect of optimal power allocation on the performance of communication systems utilizing automatic repeat request (ARQ). Considering Type-I ARQ, the problem is cast as the minimization of the outage probability subject to an average power constraint. The analysis is based on some recent results on the achievable rates of finite-length codes and we investigate the effect of codewords length on the performance of ARQ-based systems. We show that the performance of ARQ protocols is (almost) insensitive to the length of the codewords, for codewords of length $\ge 50$ channel uses. Also, optimal power allocation improves the power efficiency of the ARQ-based systems substantially. For instance, consider a Rayleigh fading channel, codewords of rate 1 nats-per-channel-use and outage probability $10^{-3}.$ Then, with a maximum of 2 and 3 transmissions, the implementation of power-adaptive ARQ reduces the average power, compared to the open-loop communication setup, by 17 and 23 dB, respectively, a result which is (almost) independent of the codewords length. Also, optimal power allocation increases the diversity gain of the ARQ protocols considerably.